The Nernst Heat Postulate, or the Third Law of Thermodynamics is sometimes rendered, "The entropy of a perfect crystal at absolute zero temperature is zero" and is clearly worded in classical terms. There is a nonzero number of bits needed to specify the deviation from the unflawed version of the crystal. Likewise an imperfect crystal will have entropy "frozen into" the deviations of the actual crystal from an unflawed version. If these degenerate ground states are not equiprobable, the entropy is $S = N_G k_B \sum\limits_j p_j \log p_j$, where $p_j$ are the probabilities for finding the state in its $j^$ ground state. For example, there may be several states a system can be in, all with the same, minimum ground state energy, and the entropy will therefore be $S=k_B \log N_G$, where $N_G$ is the number of degenerate (equal energy eigenvalue) distinguishable ground states a system can be in and $k_B$ the Boltzmann constant. Some systems can be in their ground state and still have a nontrivial state.
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